CHAPTER 4. CONCLUSIONS AND RECOMMENDATIONS

Study 1 showed that a pavement treatment can increase the proportion of double-lane yields that are detected and decrease the amount of time required to detect the yields. False detections of yields were not reduced by the treatment, and this problem would still need to be addressed.

Study 2 showed that motorists might stop long before they reach either the crosswalk or the roundabout exit, thus rendering pavement treatments in the exit ineffective. Before sound treatments similar to the one evaluated in these studies can be made to work, the frequency of motorists' yielding would need to increase, the location of the yields would need to be consistently closer to the crossing, motorists who yield would need to show more consistent patience, and the problem of false yield detection would need to be solved.

A reliable yield detection system that did not rely on where motorists stop might be effective without changes in motorist behavior because wait times for double yields were relatively short.

It is possible that a pavement treatment similar to that used in these studies would be effective at single-lane roundabouts. Study 1 showed that the second vehicle to yield is difficult to detect when it stops in the far lane, but is quite easy to detect when it stops in the near lane. Single-lane roundabouts do not present these challenges and might allow higher detection rates than were observed in study 1; however, single-lane operations were not observed in these studies, and the hypothesis that pavement treatments would be effective in the single-lane case requires empirical testing.

The finding that motorists tend to stop well upstream of the crosswalk may suggest that roundabout crosswalks should be moved two or more vehicle lengths from the inscribed circle. Such a design would reduce the likelihood that vehicles yielding to pedestrians would obstruct the circular roadway. It might also increase the likelihood that an effective pavement treatment to cue visually impaired pedestrians can be devised. This hypothesis, too, requires empirical testing. Moving the crosswalks farther from the circular roadway may change driver behavior in several ways. For instance, it might decrease driver willingness to yield. Moving the crosswalks farther from the circular roadway would increase pedestrian travel distance; therefore, the effects of situating the crosswalks at a great distance from the circular roadway would need to be carefully studied to ensure any benefits that might result are not offset by a loss in benefits.